** Description changed: - In mantic, we migrated livecd-rootfs to use losetup -P instead of - kpartx, with the expectation that this would give us a reliable, race- - free way of loop-mounting partitions from a disk image during image - build. + [impact] + In mantic, we migrated livecd-rootfs to use losetup -P instead of kpartx, with the expectation that this would give us a reliable, race-free way of loop-mounting partitions from a disk image during image build. In noble, we are finding that it is no longer reliable, and in fact fails rather often. It is most noticeable with riscv64 builds, which is the architecture where we most frequently ran into problems before with kpartx. The first riscv64+generic build in noble where the expected loop partition device is not available is - https://launchpad.net/~ubuntu- + https://launchpad.net/~ubuntu- cdimage/+livefs/ubuntu/noble/cpc/+build/531790 The failure is however not unique to riscv64, and the autopkgtest for the latest version of livecd-rootfs (24.04.7) - an update that specifically tries to add more debugging code for this scenario - has also failed on ppc64el. - https://autopkgtest.ubuntu.com/packages/l/livecd-rootfs/noble/ppc64el + https://autopkgtest.ubuntu.com/packages/l/livecd-rootfs/noble/ppc64el The first failure happened on November 16. While there has been an update to the util-linux package in noble, this did not land until November 23. + + The losetup usage has been backported to Jammy, and sees frequent + failures there. + + [test case] + The autopkgtests will provide enough confidence that the changes are not completely broken. Whether the change helps with the races on riscv can be "tested in prod" just as well as any other way. + + [regression potential] + If the backport has been done incorrectly, image builds can fail (and the autopkgtests will fail if it has been completely bungled). This can be quickly handled. There is no foreseeable way for this to result in successful builds but broken images, which would be a much more difficult failure mode to unpick.
-- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to util-linux in Ubuntu. https://bugs.launchpad.net/bugs/2045586 Title: livecd-rootfs uses losetup -P for theoretically reliable/synchronous partition setup but it's not reliable Status in linux package in Ubuntu: New Status in livecd-rootfs package in Ubuntu: Fix Released Status in util-linux package in Ubuntu: New Status in linux source package in Jammy: New Status in livecd-rootfs source package in Jammy: New Status in util-linux source package in Jammy: New Status in linux source package in Mantic: New Status in livecd-rootfs source package in Mantic: New Status in util-linux source package in Mantic: New Status in linux source package in Noble: New Status in livecd-rootfs source package in Noble: Fix Released Status in util-linux source package in Noble: New Bug description: [impact] In mantic, we migrated livecd-rootfs to use losetup -P instead of kpartx, with the expectation that this would give us a reliable, race-free way of loop-mounting partitions from a disk image during image build. In noble, we are finding that it is no longer reliable, and in fact fails rather often. It is most noticeable with riscv64 builds, which is the architecture where we most frequently ran into problems before with kpartx. The first riscv64+generic build in noble where the expected loop partition device is not available is https://launchpad.net/~ubuntu- cdimage/+livefs/ubuntu/noble/cpc/+build/531790 The failure is however not unique to riscv64, and the autopkgtest for the latest version of livecd-rootfs (24.04.7) - an update that specifically tries to add more debugging code for this scenario - has also failed on ppc64el. https://autopkgtest.ubuntu.com/packages/l/livecd- rootfs/noble/ppc64el The first failure happened on November 16. While there has been an update to the util-linux package in noble, this did not land until November 23. The losetup usage has been backported to Jammy, and sees frequent failures there. [test case] The autopkgtests will provide enough confidence that the changes are not completely broken. Whether the change helps with the races on riscv can be "tested in prod" just as well as any other way. [regression potential] If the backport has been done incorrectly, image builds can fail (and the autopkgtests will fail if it has been completely bungled). This can be quickly handled. There is no foreseeable way for this to result in successful builds but broken images, which would be a much more difficult failure mode to unpick. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2045586/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp